Continuation of Burkitt's lymphoma (BL) prospective studies, including epidemiological and virological studies in the West Nile. Malaria-related BL studies where EBV serological tests will be performed on selected portions of the population in Tanzania also will be continued. Genetic markers associated with NPC will be continued. Two HLA's previously identified in Chinese from Singapore and Hong Kong NPC will be followed from the Singapore group and search of HLA associated with NPC in Tunisia will also be continued. "Ia-like" antigens screened previously from serum from multiparous women in the Chinese community in Singapore will be followed. The work on mixed lymphocyte reaction (MLR) and primes lymphocyte transformation for investigation of D locus antigen will also be continued. IARC will maintain the serum bank by aliquoting the the serum samples, storing the samples, and maintaining the complete records (clinical and virological testing data).